• Kilpatrick, D.J.
  Biometrics Division of the Northern Ireland Department of Agriculture
  
• Sanderson, J.M.
  Forest Service of the Northern Ireland Department of Agriculture
  
• Savill, P.S.
  Department of Forestry, Oxford
  

An experiment to test the effect of different stand densities on the growth of Sitka spruce was established in 1960 at Baronscourt, Northern Ireland. Five respacing treatments applied to an 11-year old stand gave stand densities between 320 and 2900 stems ha^-1. Results up to an age of 31 years are presented when average top height was 18.5 m. A yield model is developed based on the experimental results to estimate volume and other crop variables for initial crop densities of 1000-3000 stems per hectare and for top heights of 15 to 22 m.